Double-stckle lawn mower



y 22, 1952 J. D. PIRTLE 2,603,935

DOUBLE-SICXLE LAWN MOWER I 5 I R2 l INVENTOR.

ATTORNEYS July 22, 1952 J. o. PIRTLE 2,603,935

DOUBLE-SICKLE LAWN MOWER Filed Feb. 16, 1949 s Sheets-Shet 2 I II I II I ll ll l l 1 I I II I II I ll I II I II I II I INVENTOR.

A'I'I'D RN EYS July 22, 1952 J. D. PIRTLE 2,603,935

DOUBLE-SICKLEY LIAWN MOWER Fi led Feb. 16, 1949 5 Sheets-Sheet 5 as 80 v 81 INVENTOR. 7 $4 t/a z a PZEQ ZZ 5'5 4 ATTORNEYS July 22, 1952 J. D. PIRTLE 2,603,935

DOUBLE-SICKLE LAWN MOWER Filed Feb. 16 1949 :5 Sheets-Sheet 4 INVENTOR- ATTORNEYS July 22, 1952 7 J. D. PIRTLE 2,603,935

DOUBLE-SICKLE LAWN MOWER Filed Feb. 16 1949 5 Sheets-Sheet 5 :44 1 Lu 91 m 95' 9 ALE:

I N VEN TOR.

%. ATI'CI RN EYS Patented July 22,1952

. p r a. v v t J 12,603,935 a l '7 "D U LE-stone LAWIfI"MOWEIt* losephrna vris Pirtle; SiremL WZi a Applieationll leliruary 1s, 1Q4Q,. Serial..No. term z'Glttimss (orte -zsar I I This invention relates-todawnmozwersr The objecti'of" the 'irrventton istoprovfde' 'a I'awnn ower'in which the cutti-ng is done'bya'pair ofblad'es moving in opposite directions.

fgtn'other object ofithe'invention iSTfiOiDIUVlIdG' a lawnmower having oppositely movingyrugged'ly constructed; cutting blades projecting from "the frame forwardly thereof wherebytthfe grass may be clipped neatly and close, to] growing fitrees,

shrubs, and the like, without injuring same.

In the accompanying drawings iorming apart o'fi'this application and in "wl'ri'chv like numerals are used to designate. like'parts throughoutithe Same; ,l v Figure. 1' 'i'sla top planyvi'emz oftheil'awnmower with parts broken away and'in section, according to the present inventiomj' Figure 2 1s a.;front end elevationat viewiof the Figure '3, .is a sectional view taken. on the 'line 3-3 of'Figure'l;

Figure 4 is'a sectionalwiewtaken on the line offfigure l; f V ffFigureifr is a sectional View taken on the line Figure fiis a-sectionalv'reW-taken the line "Figure 'Tisanend elevationafviewof the'c'utting bla-d'es; v

Figure 8*is asectional'view t'akenon the, line 8-8 of Figure 3; 5 -'Figure--9 i's-a sectional view-showing the overrun-clutch;

- -*Figure- I0 is a top" plan view, -with-parts broken awayand in section; of a "modified-lawnmower trio: .rnotor,' according: to the present-invention: i-nriigure 1 1 isa vertical sectional View of the lawnmawerotrfiigurfe 105;: I v

Fi'gu-reIl Z is a silie-elevational viewshowi ngq the motortand support therefor; l I

1 Figure; I3 is a sectional yiew taken onthe line l3-'-'l3"of Figure ll e Figure 114 is a View showing a modi fifedfconstru'c'tion'for'the'cuttingblades: 'Figure l'5'is' a ,detailflshowi-nga section" ofion'e of; the cutting blades.

Referring in detail to'pFigures '1' through 9 of the drawings, the lawnmower comprises a hollow fram'e3'lI'w'hich is provided therein-with bearings 3i for 'rota'tab'l y supporting "the main axle 32". Mounted" on each end of theaxle 32fs aground engaging wheef'33f and each wheel 33 .may' he provided with asuitabl'e rubber treadflfl. A pair of spacedparal'leI bracketsai" are'supported on'the frame 30 and the brackets haven.

portion projecting rearward'ly-from thefi'ame.

A pair of collars 36 support alcylindricaltrod 3'1; and the. collars '36 are connectectto the-brackets 35. by suitable bolt. and nut assemblies 38. A handle. 39 projects 'rearwardly" from the r od 31- fonmoving the lawnmower across the" grass to he cut. Iheheightof the handle 39 above the ground'may be conveniently adjusted so thatthe operator can. comfortably operate j the. flammmower, ahdlthis adjustment is. accomplished'by loosening thebolt and nut assemblies 31! wherelm the.v bracketsv 351cm .be rotated on the 'frameiBlI to the proper location andlrthereafter bolt and nut assemblies; 3,8 ar'e tightened. v Projecting forwardly from, the framev 3'0" secured thereto, is a plurality of "inclined spaced parallel braces'40f; Arsuitableground engaging roller 4| is positioned below the braces 411' and the roller H is .supportedby'a pair of. brackets 42" which are secured to th'e 'outermost-braces 40 by screws 43.. Thenbrackets'fl are each"pro-' vided with a. slot 44, Figure 3",. and the end trunnion- A5 of theroller. 4! projects, into'the slot'ss44, whereby the. roller 4.1 is. adiustably supported by the brackets 42; H v T .Ca- .ied by the front end of 1 each of the 40.; is a clamp 46, there heinga pair .ofpspaced bearing, blocks 41 and: 48-, Figure 3, securedflto the .upper. and lower portions. of each of, the clamps 46 for a purposetobe later described; A. coversmember 4:9; issecured to each of the clamps :46: by a screw 50;. and a pin 54 projects through the: cover member 49* and down. through.

the bearing blocks 4-1and 48. A' pair atoppositely moving-,coact-ing cutting; blades 52. are arranged Tin side-by-side; relation with respect to each. other. Eachwof'theycutting; blades 52 are provided withla; plurality of spaced, forwardly projecting cutting teeth 53, :and there are:v registering slots 28 in the bladezil for receiving; there.- in-th'e .pin. 51. Each of the blades: 52 are-10f identical construction, and each blade has its rear end curved arcuately as at 54, there being 2,603,935 r f g. .i

4 pending on the speed at which the operator desires to cause movement of the cutting blades,

'7 the clutch member 6| is 'moved by means of 58 projects upwardly from the frame 39 and is secured thereto, and rotatably supported in the gear housing 30 by means of bearings 59 is a splined shaft 60. A clutch member: 6| is mounted for longitudinal movement along the splined shaft 60, and the clutch member'6l is caused to rotate as the shaft 60 rotates. causing movement of the v clutch member 6| along the splined shaft 69, there is an annular groove 62 formed in the clutch member 6|, Figure 8. A pair of spaced opposed prongs (Hand 64 ro tatably ridein thegroov'e 62, Figure 4, and the prongs are carried by a yoke 65 which is moved by a lever 66 having a knob 61 on its upper end. The actuating lever 66 is pivot'ally connectedto the gear housing 58 as at 68. V

The clutch member 6| fcarries'a pair of'spaced parallel gear wheels 69 and lllwhich are adapted to be moved into and out of engagement with the gear wheels 56 and 51 whereby rotation of the main axle 32 willselectively cause rotation of the splined shaft 60. *Secured to one end of the lever 66. Thus, the clutch member 6| is moved so that either the gear 69 is in engagement with the gear wheel 56 on the main shaft, designated 32, or else the clutch member 6| is positioned so that the gear 16 thereon is in engagement with-the gear wheel 51 on the main axle- 32. Thus, different speeds of 'rotation of the splined shaft 69 can be obtained, and rotation of the splined shaft 69 causes a back and forth movement of the arm 12 which thereby causes an oscillation or rocking movement of the shaftJlB. Oscillation of the shaft 18 causes ber 19 does two things; first, it causes the lowerthe splined shaft'EfI-is a crank H and an arm .gearhousing, 58 and, into a casing 75 which projects forwardly from the gear housing 58 and is' secured thereto. A ball and sdcketjoint 16 connects the front end'of the arms l2 to a crank" and the crank 11 is secured 130N911 oscillating rock'shaft l6. v r Thelower endof the rock shaft 78 carries afsupporti'member 19' which has projecting therefrom'a finger B9 and the finger 89 projects into the cutoutj55 in the lowermost of the cutting blades 52. A'secondsupport member!!! is arranged adjacent to the ,supportmember 19, there being a brace 82 extending between-the pair of intermediate 'members and secured thereto for rotatably] supporting the support members l9and BL. Thesupport member 8| is provided with a; finger 83 which projects'into the ,cutout 55 in the uppermost of the cutting blades 52. The support member 19 is provided with aplurality of gear teeth 84, Figures, ands, which mesh withgear teeth 85 on the support member'Bl, whereby oscillation of; the rock shaft 18 causes the cutting blades'52 'to'-m ove inopposite directions "to, cut; the grass." Arranged adjacent 'each' wheel 33 is a conventionaloverrun clutch 21, Figures 1 and "9, whereby the lawnmower will continue to operate during turning of'ithe lawnmower. l

In operation of' the machineof- -Figures--l-9, the lawnmower is pushed alon'g the ground by the handle'35 -which may be'adjusted to. any height desired, and as the lawnmower moves, the main axle 32 will rotate. The actuating-lever 66 may be positioned so that neitherof the gears 69 and '16 are arranged in engagement with the gears 56 and 5'! on the main shaft 32, whereby the cutting blades will not be actuated. HWhen grass is 'tobe cut, dependingon whether or not'the grass being cut is coarse or fine, or.de.

most blade 52 to move back and forth since the finger 8D is arra ged in engagement with the .cuteout 55, and secondly. oscillation of the support member 19 causes an oscillating movement of the support member-"8| through the meshing teeth 84 and 85. "This oscillating movement of the support'member 8| causes the' uppermost cutting blade 52 to move back and forth since the finger 83 is projecting through the cor responding cut-out 55 therein. 1

Referring'to Figures '10, 11, 12, and 13 of, the drawings, there is shown a lawnmower having the sameconstruction' and op'eration as the previously described machine, except that theblades 52 are caused to move in opposite directions to cut the grass,by means of an electric motor 86, This lawnmower comprises a pair: of spaced ground engaging wheels 81 which aremounted on oppositei'ends of the axle- 88. The axle '89 isrotatably supported in a frame 89 and projecting upwardly from the frame 89 and secured thereto is pulley 92.

a'housing 90 which supportsthfe motor 86, the motor" 86 being adaptedtobe connected to a source of suitable electrijcalenergy; by meansof a jfcable 9 l Depending from, the .motor 86 is a drive shaft 9| which has mounted thereon a jProjecting.forwardlyffrom the frame 89 and securedther'eto is'a hollow casing '93 which rotat ablysupports a driven shaft 94. Mounted on the driven shaft 94 is, a pulley 95, there being a suitablebelt96ftraiinedbetweenthe pulleys 92 and 95'. Mounted on the, lower end of the driven shaft 94 is a spur. gear 91' which is arranged in meshing engagement with a'reduction gear 98 which is rotatably and dependingly supported in the casing 93 by means of a short. shaft-99.

, A pin I06 pivotally connects a'first link [ill to theu'nder surface of the reductiongie'ar 98, and a second link I62 has one of itsends'pivotally connected to the link'llll by a pi'n-l'03,. Figures 11 and 13. The other. end of the li'n'kf 02 issecured to an oscillating rock 'shaftlllfl which functions in the same manner as the previously described rock shaft 18to thereby cause or impart an oppositely oscillating movement. to the coacting cutting blades 52. I

Inuse of the ;motor actuated lawnmower of Figures 10, 11, 12, and 13, the motor 86 i s:e1ec trically actuated as desired, ,whereby the. driven mang e; will; be, .m t d hm sh. h belt and u l r a a emen andi ta ion: 1 he, driven shaft 94 will causethe ishaf-tjlfilto oscillate or rock back-an'd forth through -the;gear and link arrangement thereon. Rocking movementof the shaft Ill-l imparts 'anpscillating movement to the cutting blades 52 in thesame manner as was im-,

' 5 parted to the cutting blades of the lawnmower in Figures 1 through 9.

Referring to Figure 14, there is shown a slightly modified pair of cutting blades for the lawnmower. The cutting blades are each designated by the numeral I05, and each cutting blade is provided with a semi-circular shaped offset portion I06 which extends longitudinally along each blade intermediate its ends. This offset portion is arranged to the rear of the cutting teeth Ill! and serves to strengthen the cutting blade whereby the blades will remain undamaged during normal use. The cutting blades I05 are used in the same manner as the previously described cutting blades 52.

From the foregoing it is apparent that a lawnmower has been provided which will effectively cut grass and the like by an oscillating, opposite movement of a pair of coacting cutting blades. The blades may be either actuated by an electric motor as shown in Figures 11 through 13, or the blades may be caused to actuate by being operatively connected to the axle 32 of the lawnmower, Figures 1 through 9. The cutting blades of the machine project forwardly therefrom whereby grass and the like can be cut extremely close to a fence so that it will be unnecessary to later trim the lawn after the grass has been cut. The cutting blades are identical in configuration whereby the blades can be readily interchanged and the blades can be easily removed from the machine in order to file or sharpen their edges. The handle for moving the machine along the ground is adjustable so that the operator can conveniently use the lawnmower and in the lawnmower of Figures 1 through 9, the gear arrangement is such that the lawnmower may be rolled freely along the ground without operating the cutting blades 52. Further, the gear arrangement is such that a high speed and low speed is obtainable.

While I have shown and described preferred ground engaging wheel mounted on each end of said axle, a grooved rubber covering secured to each of said wheels, a pair of spaced parallel gear wheels having different diameters arranged intermediate the ends of said main axle and secured to the latter, a vertically disposed gear housing 6 projecting from said frame and secured thereto, a horizontally disposed splined shaft rotatably supported in said gear housing, a clutch member splined on said last named shaft, whereby rotation of said last named shaft causes rotation of said clutch member, a pair of spaced gear wheels having different diameters secured to said clutch member and mounted for movement into and out of meshing engagement with the gear wheels on said axle, a hollow casing projecting forwardly from said gear housing and secured thereto, a vertically disposed rock shaft projecting into said casing, means operatively connecting said rock shaft to said splined shaft, a plurality of spaced parallel inclined braces projecting forwardly from said frame and secured thereto, a clamp carried by the front end of each of said braces, and a pair of oppositely moving cutting blades supported by said clamps and operatively connected to said rock shaft.

2. In a lawnmower, the combination with a frame, a main axle carried by said frame, a pair of ground-engaging wheels mounted on said axle, a pair of oppositely moving cutting blades projecting forwardly from said frame, said cutting blades being arranged in superposed coacting relation with respect to each other, a handleadjustably connected to said frame, a ground-engaging roller supported by the front end of said frame and interposed between the ground-engaging wheels and the cutting blades, means operatively connecting said cutting blades to said main axle, said means comprising a shaft arranged in spaced parallel relation with respect to said main axle, gear means for connecting said axle to said shaft, clutch means for causing said shaft to be driven at different speeds, a first crank secured to one end of said shaft, an arm having its rear end pivotally connected to said first crank, an oscillating rock shaft arranged at right angles with respect to said arm and pivotally connected thereto, and means connecting the lower end of said rock shaft to said cutting blades.

JOSEPH DAVIS PIRTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,511,501 Campbell Oct. 14, 1924 1,779,723 Ashby Oct. 28, 1930 2,329,881 Clapper Sept. 21, 1943 

